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Health effects from ingesting too much vitamin C

Dear Alice,

What happens if you got too much vitamin C?

Dear Reader,

While vitamin C (a.k.a. ascorbic acid) plays a key role in the absorption of iron, the growth and repair of tissues in various parts of your body, and helps to fight against the common cold, it’s still possible to take in too much. While getting a little more than your recommended daily intake may not present much of a risk to your health, taking in too much could lead to a number of undesirable side effects. How much is too much, you ask? Well, that depends on how much you take in and if you have certain pre-existing medical conditions (more on that later).

Where does vitamin C come from? Since the human body can’t produce vitamin C on its own, it's recommended you get the amount you need from the foods you eat. Luckily, vitamin C is a water-soluble vitamin that’s found naturally in some foods and added to others. Fruits and vegetables such as oranges, green peppers, cantaloupe, strawberries, fresh tomatoes, and potatoes are some of the best sources of vitamin C.

While ingesting a little extra vitamin C is probably not going to cause any major health issues (excess is normally removed from the body when you pee), especially large doses may result in some unpleasant symptoms due to unabsorbed vitamin in the intestinal tract. Possible side effects associated with too high vitamin C intake include:

To avoid these possible effects, your best bet is to stick to the Recommended Dietary Allowance (RDA) of 75 to 90 milligrams (mg) a day (for men and women ages 19 and older — those who are pregnant, lactating, or who smoke have slightly higher recommendations), with an upper limit of 2,000 mg. While 2,000 mg may be the maximum threshold for most folks, those with some pre-existing health conditions might be negatively affected by consuming smaller doses of vitamin C. For those living with thalassemia, hemochromatosis, sickle cell anemia, or diabetes, seeking medical advice is recommended to determine how much vitamin C is best — because taking too much may cause serious side effects. On the other hand, there are certain groups of people who may have insufficient levels of vitamin C, including people who smoke, use nicotine patches, or folks who have limited food options. The use of certain medications may also interact with vitamin C in the body. For example, taking over-the-counter (OTC) medications, such as aspirin, acetaminophen, and other nonsteroidal anti-inflammatory medications (NSAIDs) while taking vitamin C supplements can cause the level of the drugs in your blood to rise. Also, taking oral contraceptives (birth control pills) or hormone replacement therapy with vitamin C supplements can decrease the effects of estrogen in the body.

If you’re concerned about your vitamin C intake, it’s wise to speak with your health care provider about the amount that’s right for you. You might also speak with a registered dietitian to determine what sorts of vitamin C-rich foods you can incorporate into your diet. Remember, when it comes to vitamins, more may not always be better!